package com.yh.crystal.chinaunionPay;

import java.security.MessageDigest;

import cn.hutool.core.util.StrUtil;

public class EncodeUtils {

	private static final String charset = "UTF-8";

	private static final char[] HEX_DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', //
			'a', 'b', 'c', 'd', 'e', 'f' };

	/**
	 * SHA256 签名算法 encode By SHA-256
	 * 
	 * @param str
	 * @return
	 */
	public static String encodeBySHA256(String str) {
		if (StrUtil.isBlankIfStr(str)) {
			throw new RuntimeException("should not be blank!");
		}
		try {
			MessageDigest messageDigest = MessageDigest.getInstance("SHA-256");
			messageDigest.reset();
			messageDigest.update(str.getBytes(charset));
			return getFormattedText(messageDigest.digest());
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
	}

	/**
	 * Takes the raw bytes from the digest and formats them correct.
	 *
	 * @param bytes the raw bytes from the digest.
	 * @return the formatted bytes.
	 */
	private static String getFormattedText(byte[] bytes) {
		int len = bytes.length;
		StringBuilder buf = new StringBuilder(len * 2);
		// 把密文转换成十六进制的字符串形式
		for (int j = 0; j < len; j++) {
			buf.append(HEX_DIGITS[(bytes[j] >> 4) & 0x0f]);
			buf.append(HEX_DIGITS[bytes[j] & 0x0f]);
		}
		return buf.toString();
	}

}
